Casting one piece, Diferent metals

Hello All
I’ve kind a been setting in the back row watching
helping a little here and there now I have a question. Surprise
Surprise! I want to hear from anyone who has cast a single
article with two or more metals. I am looking not only to cast
using different colors of gold but also gold and silver. The
knowledge I need is this: Any difference in the burnout cycle or
the casting temp? Which metal should I cast first? Any special
prepping of the casting before adding more wax and investing for
the second/third casting cycle? Any additional fluxing involved
other than the usual addition of borax to the metal while
melting? Yep! You guessed it, I need all the info I can get. My
method of casting is centrifuge. Any help along these lines would
be appreciated.

Best Wishes to You All *<:-)
Merry Christmas
Tom Timms

@TTimms4353

Are you the same Tom Timms that taught metals at Univ. of Tenn.
in 1972-73? If so, I was in your Design class. My graduate work
was in Weaving and Textile Design. Let me know…Gini Rollins